AI legal tools, reviewed: Harvey vs Spellbook for contract review

Contract review is the work lawyers least want to bill and clients least want to pay for — which is exactly why it was one of the first legal workflows AI went after. Two products now dominate the conversation: Harvey, the enterprise legal AI backed by big-firm money and big-firm ambitions, and Spellbook, the Word-native copilot that lives inside the document you're already drafting.

They are not really competitors in the same weight class, and that is the point. This review walks a realistic contract-redlining workflow through each tool — from first read to final redline — using vendor documentation, published pricing research, and aggregated user reviews, and flags where a human still has to stay in the chair.

What each tool actually does#

Harvey is a general-purpose legal AI platform. Built on models from OpenAI, Anthropic, and Google with legal-domain fine-tuning, it handles research, drafting, contract analysis, due diligence, and litigation support. Its Vault product can bulk-analyze up to 10,000 documents at once, and agentic workflows can take on multi-step jobs like reviewing a data room. The numbers around Harvey are enterprise-scale: an $11 billion valuation after its March 2026 round, roughly 200,000 lawyers across more than 2,400 organizations, and reported $350 million in annualized revenue by mid-2026 (legesgpt.com; costbench.com buyer reports).

Spellbook is narrower by design: an AI assistant that lives inside Microsoft Word, aimed squarely at commercial lawyers drafting and negotiating contracts. Its selling points are Word-tracked-changes redlines, customer-defined playbooks that enforce a firm's positions automatically, and a Market Comparison feature that benchmarks roughly 250 deal points against anonymized transaction data — so "is this liability cap market?" gets a data-driven answer. Its newer Associate agent handles multi-document tasks from a single instruction, similar to delegating to a junior associate. Spellbook says it serves over 4,000 legal teams.

Round 1: The redlining workflow#

Take a typical task: a 30-page vendor agreement arrives for first-pass review.

With Harvey, you'd upload the document (or point at a Vault collection) and ask for a risk-focused review: flag deviations from your standard positions, extract key terms, and summarize exposure. Harvey's strength is breadth — it can pull in legal research with citations, check compliance across jurisdictions, and, through its LexisNexis integration, cross-reference primary legal content. Third-party reviews credit it with cutting document review time dramatically — Harvey's own benchmarks claim up to 80× faster document review, a number to treat as marketing, not measurement. In practice, user reports emphasize big-firm contract review and due-diligence speedups in the 50%+ range.

With Spellbook, you never leave Word. Highlight a clause, ask for a redline consistent with your playbook, and the suggestion appears as familiar tracked changes you accept or reject. The Market Comparison feature answers "what's market?" mid-negotiation with benchmark data rather than vibes. Multi-document jobs — say, reviewing a package of related agreements — get handed to Spellbook Associate rather than the Word add-in, which reviewers note as a slightly awkward handoff between two interfaces.

Verdict on workflow: if your unit of work is one contract in Word, Spellbook's in-flow design wins on speed and low friction. If the job is portfolios, data rooms, and research-grade diligence, Harvey's scope is in a different league.

Round 2: Accuracy and the vigilance tax#

Both tools are LLM-based, which means both can produce confident-looking errors — the classic AI failure mode in legal work, where a plausible citation or a misread defined term can be worse than no help at all.

Aggregated user reviews (G2, Lawyerist summaries) converge on a consistent critique of Spellbook: it is "somewhat glitchy at times," with occasional formatting inconsistencies and the known AI tendency to make mistakes that require vigilance to catch. Harvey, similarly, is criticized in practitioner forums for outputs that read well but need verification — one Reddit thread's memorable complaint was that associates found the tool underwhelming even as partners bought in.

Neither vendor publishes independent accuracy benchmarks for contract review, and you should treat any vendor benchmark accordingly. The practical takeaway from reviewer consensus:

• Both tools reduce time-to-first-draft and issue-spotting effort, especially for routine clauses (governing law, assignment, termination).
• Both require attorney verification on anything that changes economic exposure — indemnity caps, limitation of liability, warranty language.
• Playbooks are the real accuracy lever: Spellbook's automatic playbook enforcement and Harvey's custom firm-specific tuning both reduce hallucination risk relative to a raw chatbot, because the AI is anchored to positions the firm already approved.

Round 3: Pricing#

This is where the two tools live on different planets.

Harvey publishes no price list. Third-party pricing research for 2026 puts it at roughly $1,000–$1,200 per lawyer per month on full plans, with a reported 20–50 seat minimum — an entry point of roughly $288,000+ per year for a mid-size firm. Premium add-ons push reported per-seat costs toward $2,000/month, and a LexisNexis bundle reportedly adds $400–$600 per lawyer per year (legesgpt.com, vaquill.ai, costbench.com). Median reported contract: around $175,000/year. No free trial, no self-serve plan; onboarding takes months. This is software priced for firms that can absorb six figures and spread it across hundreds of attorneys.

Spellbook is the opposite end of the market. Historically it advertised transparent tiers — around $20/month for individuals and $40/user/month for teams — and while current public pricing has moved toward custom per-seat quotes (with third-party estimates ranging from ~$89–$129/user/month for individual/team tiers and up to ~$350/user/month at enterprise), it offers a 7-day free trial and is explicitly positioned as accessible to solo practitioners and small teams (spellbook.com; hyperstart.com; softwaresuggest.com). Pricing details are in flux — treat third-party numbers as estimates and get a written quote — but the order of magnitude is unambiguous: Spellbook costs roughly what one junior associate costs in a week; Harvey costs what a practice group costs in a year.

Round 4: Security and data handling#

For contracts, data handling is a deal-breaker, not a footnote. Spellbook advertises zero data retention — documents aren't stored and aren't used to train models — backed by SOC 2 Type II, GDPR, and CCPA compliance. Harvey carries enterprise certifications (ISO 27001, SOC 2 Type II), encryption, and granular access controls aimed at big-firm infosec reviews, plus deep integrations with iManage, NetDocuments, and Microsoft 365. Both check the boxes their target markets require; Spellbook's zero-retention stance is the more aggressive posture for confidentiality-conscious users, while Harvey's enterprise posture is built for procurement committees.

Where humans still win#

After all the comparisons, the honest conclusion is that neither tool replaces a lawyer — they compress the boring middle of review work. Humans still win (and must stay in the loop) on:

• Commercial judgment calls. No model can decide how hard to push back on a liability cap when the client relationship matters more than the clause. Market data helps; it doesn't choose.
• Novel or cross-jurisdictional terms. Reviewers consistently note that complex cross-border contracts exceed what inline suggestions handle well. That's Harvey's research-adjacent territory, and even there, verification is mandatory.
• Negotiation strategy. Both tools redline; neither negotiates. Reading the counterparty — knowing when to trade a term for speed — is still a human skill.
• Ultimate accountability. The malpractice exposure sits with the signing attorney, not the AI. Every bar association guidance on the topic lands in the same place: AI output is work product, and the lawyer who relies on it owns the result.

The takeaway#

Buy Harvey if you're at a firm or company big enough that the price disappears into the legal budget, and your work spans research, diligence, and litigation — not just redlining. Buy Spellbook if you live in Word, review contracts clause-by-clause, and want AI help without an enterprise procurement cycle.

And whichever you choose: budget for the vigilance tax. The tools are genuinely good at first-pass review, and genuinely unreliable enough that the final read stays human. That gap — between a fast draft and a signed contract — is where the lawyer still earns the fee.